<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 先请求A 再请求B 再请求C

        function*getDataa(){
            console.log("A开始");
            yield setTimeout(() => {
                console.log("A成功");
                gen.next();
            }, 2000);

            console.log("B开始");
            yield setTimeout(() => {
                console.log("B成功");
                gen.next();
            }, 2000);

            console.log("C开始");
            yield setTimeout(() => {
                console.log("C成功");
            }, 2000);
        }

        const gen = getData();
        gen.next()
    </script>    
</body>
</html>